The Truth About Hayflick Limit

In the early days of Truth In Aging, I learned about something called the Hayflick Limit and the notion that cells have a limited life. I speculated that if we exfoliate regularly and dramatically — I was more concerned with retinols, deep chemical peels, laser treatments and so on — we might speed up the Hayflick Limit. As my own anti-aging beauty regimen has recently — and successfully — incorporated light peels and AHAs, as well as a retinol neck cream, I decided it was time to revisit the Hayflick Limit and the impact of exfoliation. Had I been on to something, or putting two and two together and making seven? It was time to get to the truth about the Hayflick Limit.

What is the Hayflick Limit?

It all started with Leonard Hayflick, a scientist who has changed thinking on the mortality of cells. Let’s say you take a biopsy from my skin, take it to a lab and dissolve the “mortar” that holds together the cells, leaving individual cells. These cells, if “treated nicely” (as Doc Hayflick himself put it on an NPR RadioLab program), will divide and proliferate. Scientists used to assume that they would do so indefinitely until Hayflick discovered that cells are not immortal. Cells don’t just keep dividing forever, but eventually stop and then die. And how many times do they divide before dying? A mere 50-something times.

But why do they stop? This is where telomeres come in.

If DNA is broken there are two options after the cell cycle is stopped: repair or death. If cells divided without telomeres, they would lose the end of their chromosomes, and the necessary information it contains. They are often described as being like the tips on the ends of shoelaces that stop them unraveling. Telomeres shorten every time a cell divides until they shorten to a critical length. And that’s when the cell dies.

What about skin cells?

Someone once left a comment on Truth In Aging saying that skin cells don’t have a Hayflick Limit. Stem and cancer cells keep on going, but all other cells in our bodies have their 50-or so limit. An article on Beauty Brains was a useful starting point for my research into this. The short answer is that they do.

A keratinocyte is the predominant cell type in the epidermis, the outermost layer of the skin, accounting for about 90% of the cells found there. They start out from keratinocyte stem cells reside in the basal (deep) layer of the epidermis. Then they differentiate (become normal cells) and migrate to the surface of the skin. And that is where they reach their Hayflick Limit and die.

And that is why exfoliation leaves the skin looking younger and more radiant. It removes those dead cells.

But will deep exfoliation speed up the Hayflick Limit?

If exfoliation techniques are doing more than just swiping off cells that have already reached their Hayflick Limit, are we speeding up the process? Beauty Brains says not — because the stem cells in the stratum basale reproduce without limit to make more keratinocyte cells. Sounds reassuring, but unfortunately it is more complex than this. Stem cells do die. Embryonic stem cells are not subject to the Hayflick Limit, neither are cells in the muscles. Some adult stem cells may also not reach their Hayflick Limit, but science seems hazy on this. One scientific study estimates that stem cells in mice live for a few months or at most three years before shuffling off their mortal coil. So, for now, I’m not counting on a stash of invincible stem cells in my deep epidermis to keep replenishing my skin.

OK, but is exfoliation a good thing or a bad thing?

SmartSkincare.com makes a good point about cells that have reached their Hayflick Limit. They don’t always die, but hang about: “Instead they enlarge, lose their useful functions, slow down and just sit there lazily interfering with younger cells.” The skin of older people has three times “senescent” (past their sell-by date) fibroblasts as young skin. Research has shown that cells near their Hayflick Limit secrete collagenase, which breaks down collagen. Not a good thing.

So helping to clear them off the surface of the skin would seem to be a good thing, especially as we age. I am thinking that AHAs and BHAs are probably a good thing and can be used regularly, with plenty of antioxidants to go along with them. Retinol and microdermabrasion I would confine to limited use, stopping when damage has been removed and is repairing. Deep peels, laser treatments and so on that traumatize cells into dividing themselves would seem to speed up the Hayflick Limit.

In the course of my research, I found out that when cell apoptosis (death) occurs, phospholipids engulf the cell fragments, degrade the individual chromosomes and carry them out of the body as waste (source). Phospholipids also help retain moisture and, therefore, sometimes appear in anti-aging skin care. It now seems there is another reason — dead cell spring cleaning — to look out for them. Phospholipids are featured in BRAD Sublime Youth Creator Gel Cream ($245), Apothederm Firming Serum ($75) and in Step 2 (Step 1 will give you all those AHAs and BHAs) of Dr. Dennis Gross Medi-Spa Peel($110 in the shop).

Can we do anything to extend the Hayflick Limit?

Hayflick himself says that cells will stop dividing and hang around indefinitely if frozen. As it’s not very practical to freeze ourselves, what else is there? L-carnosine is an amino acid that actually extends the Hayflick Limit. As mentioned above, skin cells can only reproduce themselves around 52 times, while carnosine extends this to over 60 times. Prana Reverse A($48 in the shop) has carnosine as an intelligent counterpart to retinol.

There are some relatively new actives that work on our telomeres. One is teprenone, also known as Renovage. There's also a natural version found in astragalus. They work by stabilizing the telomeres so that they won’t shorten, and this can extend the life of the cell by one third.

LED light therapy and ultrasound also work at the cellular level. LED increases production of ATP (the energy engine of cells) leading to increased cell proliferation and migration (particularly by fibroblasts). Ultrasound energy causes the movement of fluid waves against the cells. This may result in alterations in ion concentrations and stimulate an intracellular cascade, resulting in increased fibroblastic activity and collagen formation. Truth Vitality Lux Renew ($279 in the shop) has LED light and ultrasound.

Hi Marta, Would using the Ultrasound on the Truth Vitality Lux Renew speed up the hayflick limit?

April 28, 2016

by Marta

Anna, it's cell by cell. Not all your skin cells are going to reach their limit at the same time. At 30 you have more than enough newer cells to not notice anything. It would be only be visible if you dramatically sped up the process with excessive exfoliation.

April 28, 2016

by anna

So what happens if a person let say age 30 reaches that limit? What happens to her skin? what then?

October 27, 2015

by Marta

Susan - thank you for the phrase "aging is a full-time job". Might just have to use that. Hi Kimberly, I haven't seen any meaningful research on carnosine supplements and aging or skin. Most of the studies are on muscle mass although I found one animal study that showed supplements (along with alpha lipoic acid) increased antioxidant levels. I have added this reference to the carnosine entry in our ingredients directory: https://www.truthinaging.com/ingredients/carnosine

October 27, 2015

by Kimberly

Thank you so much for the informative article, Marta. I'm glad you researched the Hayflick limit for us. It certainly is a thought provoking article. I was glad to hear you mention telomere shortening, as I use a particular product that incorporates teprenone (Renovage). I take L-carnosine supplements, so I'm hoping they are helping my skin internally. With regards to extending the Hayflick limit, what are your thoughts and/or findings on taking the L-carnosine supplements?

October 27, 2015

by Gale

Great article & thought provoking. There just has to be so much more to the story that we don't know. I mean if we who are using retinoids, exfoliants, clarisonics, etc... keep using this regimen & our cells reach their hayflick limits, what is going to eventually happen? The skin will just all droop or fall off our faces? I think not. The body seems to have a remarkable way of regenerating itself even if it is more slowly during our latter years. I wonder if any new clinical research on burn patients could contribute to this discussion. I hope this is a subject that continues to be researched & investigated.

October 26, 2015

by Susan

Wow, thank you for such informative material. I never knew about the Hay flick Limit. Now that I have entered my 50s, I am more cognisant of what I do to my skin, let alone put on it. Thank you for always providing great infomation. It is a full-time job, aging. Information is power. I now must use my Truth Vitality Lux more religiously!

October 22, 2015

by Pat

Great article. Ever since I learned about the Hayflick limit a few years ago, I wondered if exfoliation was using up my limited cell reproductions. Thanks for explaining.

October 22, 2015

by Don

Thank you Marta for this fascinating (& enlightening) article. Perhaps one day it will increase far beyond the 52-60 times.

October 22, 2015

by PAMELA G

I'd begun to feel that phospholipids were important for my skin based on recent experience, but didn't know specifically "why". Thanks for sharing this information in your article!!

Although in the past I've used different brands containing phospholipids, My 63 yr old skin is definitely being served best by the Brad products. Noticeable difference in my skin quality since beginning their use over a year ago. In the past I've not had as much luck with some other TIA members' "Holy Grail" products. Was almost ready to throw in the towel and just accept that my skin wouldn't ever improve. After learning about Brad on TIA, I tried it and found it delivered what my particular skin really needed.